This invention relates to fire-retardant or flame retardant preparations, and also to articles treated with such preparations.
There is an increasing need in industry, in public places, and in the home for treatment of flammable articles to render them fire resistant or flame resistant. This requirement applies to industrial clothing. It also applies to international building materials such as lumber, plywood, and other decorative materials in the commercial and industrial marketplace typically associated with hospitality, educational, and health care facilities. Flame proofing or flame retardancy is now being required even for displays and the like. Flame proofing and fire proofing is also desirable, if not required, for upholstered furniture, for vehicle interiors, and for industrial gloves and outer clothing. Flame retardancy is also required in some situations for mattresses and is desirable for paper products, wall hangings, and other flammable items.
According to a recent study of the National Fire Protection Association, about two-thirds of all home, hotel, and office fires originate on decorative materials, i.e., upholstery, wall coverings, carpets and rugs, draperies, and paneling, These items are generally installed after construction is complete or nearly complete. In industrial and commercial facilities whose decorative materials are mandated to be fire resistant, problems can occur in that if materials, in fact, do meet fire codes on new constructions upon completion, there is no way to ensure or check for the continued effectiveness of the decorative material's fire retardancy during or after initial construction. Significant problems in this area of fire protection are first, the ability to ensure that the treatment has been properly applied, and second, the ability to inspect the status of the flame- or fire-retardant treatment at future dates.
Because of the decorative nature of many of these materials, it is important also that the flame-retardant or fire-retardant treatment not discolor the materials or otherwise degrade their appearance.
The conventional method of treating these articles for fire or flame retardancy is to apply an aqueous solution of an inorganic salt having fire-retardant characteristics, and then to dry the article. However, because these conventional treatments involve a soluble inorganic salt, the durability of the treatment is quite limited. This is because the salt dissolves or leaches out in moisture and can be washed away by laundering or dry cleaning, or simply by perspiration or high humidity conditions. Another problem of conventional treatments is that the inorganic salt employed as a fire-retardant can bring stiffness and/or discoloration to the treated article. Furthermore, because the inorganic salt can be somewhat toxic, the amount that can be employed for a given area of fabric is somewhat limited.
It would be desirable to supply the treatment as a self-application kit, e.g. for use by schools, parents, theater groups, etc. This would provide a safe and simple means for Such a self-application kit would, of course, facilitate the treatment in place of existing drapes, carpeting, etc., without requiring their removal and reinstallation.
Another problem with previously-proposed flame- or fire-retardant treatments is their incompatibility with synthetic, high-polymer content fiber products. This is a problem derived from the use of water soluble inorganic salts, which have little if any tendency to bond to the surface of they synthetic organic polymer fibers.
A further problem is that with a generally colorless and textureless treatment, the untreated product appears the same as the treated product. Accordingly, it would be extremely desirable to provide means to detect whether an item has been treated, or whether a previous treatment is still effective. Destructive testing, i.e., applying an open flame to the decorative materials, is unacceptable in almost all instances.
One proposed solution that has met generally with success is described in U.S. Pat. No. 4,824,483. This involves a treatment that can be applied onto previously installed materials, which can be made of high-polymer content fibers, and which is quite durable. This patent, which involves the same inventor as in this improvement, also describes additives to enhance the penetration and persistence of the treatment and to give the treatment an ultraviolet detectability.
The treatment involved in that patent is an aqueous solution of ammonium sulfate, a metasilicate salt serving as a binder, and an ammonium phosphate such as monoammonium phosphate (MAP) or diammonium phosphate (DAP). To this an ultraviolet inhibitor can be added, and the inhibitor disclosed in the patent is a substituted disulfobenzophenone, namely disodium 2,2'-dihydroxy 4,4-dimethoxy - 5,5-disulfobenzophenone, which is commercially available from BASF Wyandotte under the name UVINUL DS-49. This compound has fluorescent properties, and will fluoresce with a color ranging from orange to lime green under strong exposure to long-wavelength ultraviolet light.
With such a system, a fire inspector can field-test the treated materials non-destructively, using an ultraviolet test lamp. This also reduces the need to rely solely on written documentation of treatment, as the effectiveness of the treatment is, or should be, visible to the inspector.
In addition, a wetting agent can be included in the treatment to facilitate penetration into the fibers. In the patent, a wetting agent is disclosed that biogrades after treatment so that further wetting after application will not affect the flame retardancy.
Unfortunately, the ultraviolet agent used in the patented formulation, i.e., the substituted disulfobenzophenone, does have a drawback in that its fluorescence is quite weak. In many cases, a zero or near-zero light condition (total darkness) is required to verify the presence of the treatment. On some materials, such as wood, the visible light is very difficult to see, even under ideal conditions. Moreover, under some conditions the ultraviolet agent does not stay in solution before treatment. Even though this does not affect the fire-or flame-retardancy, it does render the treatment impossible to verify by ultraviolet means.
For these reasons, an improved formulation has been sought in which the ultraviolet agent fluoresces at a level strong enough to be detected in the presence of normal incident light, which will be detectable on all treated material, and which will reliably remain in formulation in the treatment until application.